1-D Multipoint Auxiliary Source Propagator for the Total-Field/Scattered-Field FDTD Formulation

A multipoint auxiliary time-domain 1-D propagator is proposed for initiation of plane wave sources in the total-field/ scattered-field formulation (TFSF) of finite-difference time-domain (FDTD). The propagator is developed by making the 1-D and 2-D/3-D dispersion equations identical, leading to a multipoint 1-D stencil. A perfect match can be achieved for a plane wave propagating at an angle forming an integer gridcell ratio, which can in theory represent almost any angle. Numerical examples in 2-D show that leakage errors into the scattered field domain are on the order of finite precision (-300 dB for double precision)